Not Applicable
Not Applicable
1. Field of the Invention
This invention is in the field of equipment used in the production of fluids from, and injection of fluids into, oil and gas wells having multiple zones.
2. Background Art
Many oil or gas wells extend through multiple formations, resulting in the establishment of multiple zones at different depths in the well. It may be desirable to produce formation fluids such as gas or oil from different zones at different times, and to inject fluids such as water into different zones at different times, for the purpose of ultimately obtaining the maximum production from the well. Further, it may be desirable to produce formation fluids from one or more zones, while simultaneously injecting fluids into one or more other zones. Finally, it may be desirable to convert a particular zone from a production zone into an injection zone, after the zone is depleted.
Known equipment for these purposes usually requires pulling the completion assembly from the well, and changing or reconfiguring the equipment in the assembly, when it is desired to commence or cease production or injection in a particular zone. Further, known equipment is generally limited to the production of fluid or the injection of fluid at any given time, with simultaneous production and injection not being possible, or at least difficult. More specifically, known equipment is not capable of the simultaneous production from multiple zones and injection into multiple zones.
The present invention provides a method and apparatus for selectively injecting into a given zone or multiple zones, or producing from a given zone or multiple zones, without pulling the equipment from the well. A completion unit is positioned next to each zone of the formation, with zones being segregated by packers. An injection sleeve and a production sleeve are provided in each completion unit. Each sleeve essentially bridges between the completion string and the production string, which is within the completion string. Each sleeve is shifted, such as by hydraulic, electrical, or mechanical operation, to selectively align a conduit through the sleeve with its associated port in the wall of the completion string. When aligned with the inlet port, the conduit in the production sleeve conducts formation fluid into a production fluid path in the production string. When aligned with the outlet port, the conduit in the injection sleeve conducts injection fluid from an injection fluid path into the formation. Regardless of sleeve position, both injection flow and production flow can be maintained through the completion unit to other completion units above or below.
By selectively shifting the sleeves, selected zones can be isolated, produced from, or injected into, as desired. One or more lower zones can be injected into while one or more upper zones are produced from, or vice versa. If desired, alternating zones can even be simultaneously produced from and injected into.